1. Statement of the Technical Field
The present invention relates to the field of telecommunications and more particularly to the heuristic routing of electronic documents.
2. Description of the Related Art
Traditionally, documents have been exchanged between parties by way of hand delivery, postal service, or facsimile. More recently, the public Internet has become a highly effective medium through which electronic documents have been exchanged, particularly as attachments to electronic mail. Still, in many occasions, the use of electronic mail cannot provide an adequate medium for document transfer. Specifically, where the original copy of a document is in a hard copy format, with handwritten or non-textual elements, a facsimile device can be the preferred tool of document exchange.
Facsimile devices ordinarily exchange facsimile data with other facsimile devices over the public switched telephone network (PSTN). Specifically, as in the case of an ordinary telephone call, the calling facsimile device can establish a communicative link over the PSTN to a receiving facsimile device. Each of the devices can negotiate suitable data exchange protocols and the transfer of facsimile data can commence. Upon completion of the exchange, the received facsimile data can be transposed to hard copy form and the call can terminate. Notably, like the telephone call, connection charges can apply for the duration of the facsimile communicative link in the same way charges can accrue for a voice call between the same two locations. Where these locations are distance apart, long distance charges may apply.
To circumvent the costs associated with the conventional exchanged of a document between facsimile devices, several technologies have been developed with which facsimile data can be exchanged between facsimile devices not over the PSTN, but over the public Internet. Referred to in the art as “IP faxing”, facsimile data can be packetized and forwarded across the Internet to a network node local to the facsimile recipient. In this way, toll charges ordinarily associated with PSTN based facsimile communications and ordinary telephone calls can be avoided. Consequently, IP faxing has proven to be the bane of fax intensive business processes, such as direct marketing and broadcast faxing.
Broadcast faxing, whether IP faxing or otherwise, can be an inexact science. Specifically, at best the broadcast facsimile device can be provided only with an electronic or hard copy of a facsimile document and a list of target facsimile numbers. The validation of the numbers in the list, however, remains unaccounted for, both with respect to a proper correspondence between facsimile number and target recipient, and also with respect to the technical reliability of the underlying infrastructure required to establish a communicative link between the fax server and the target facsimile device.
For example, when attempting to transmit a facsimile to a target facsimile device at a specified telephone number, it may be the case that the specified telephone number does not in fact correspond to a facsimile device. In this case, the facsimile will not be transmitted to the target facsimile device and, in all likelihood, the actual party associated with the mis-specified telephone number will become displeased with the periodic attempts of the fax server to deliver the facsimile to the non-existent facsimile device. Mis-specified telephone numbers do not form the basis of all failures to deliver a facsimile to its intended recipient. Rather, oftentimes the underlying technology can form the basis of an inefficiently delivered facsimile.
In particular, recalling that telephone charges accrue in many cases by the minute or by the fraction of a minute, an unreliable communicatively link over the PSTN can result in the expensive process of error correction. To ensure that a facsimile is delivered over the communicative link in an error-free fashion, in many cases, an error-prone connection will require several reattempts to retransmit data which had not been successfully transmitted in the first place. Of course, the strength of error correction can be linked directly to the processing power of the transmitting and receiving facsimile devices. Accordingly, it would be preferable to establish the most reliable communicative link possible in order to minimize the retransmission of data in the course of delivering a facsimile to a target device.
One skilled in the art will recognize the importance of transmission cost in the broadcast fax and electronic document delivery market. To that end, recent renditions of broadcast IP faxing technology include least cost routing (LCR) functionality. LCR refers to the logic of a fax server in determining the lowest cost delivery method for a given facsimile—by calling the destination facsimile device directly, or by sending the facsimile to a remote fax server over the Internet which can call the destination facsimile device. Still, LCR alone cannot accommodate either mis-specified telephone numbers, or faults in the underlying communications medium. Moreover, the fundamental intent of LCR is to reduce costs, regardless of the effectiveness of the chosen method.
U.S. Pat. No. 5,862,203 issued on Jan. 19, 1999 to Wulkan et al. for TELECOMMUNICATIONS CALL MANAGEMENT SYSTEM relates to an LCR system for choosing the optimum telecommunications carrier for telephone calls made by a user. In that regard, it will be clear to one skilled in the general art of telecommunications call routing that not all carriers in a PSTN provide the same connectivity at the same cost. Rather, the Wulkan specification teaches that some carriers provide the same connectivity, albeit at different costs. Based upon this realization, the system disclosed in the Wulkan specification teaches the selection of a particular carrier to carry a telephone call based upon a set of parameters, all relating to the cost of carrying a particular phone call to its destination.
Importantly, most of the parameters in Wulkan which are selected for consideration when optimally routing a telephone call relate to the originator of the call rather than the destination. For example, the parameters include the eligibility of the caller for a volume discount, call history discounts, and the typical call duration based upon a statistical distribution for the caller. None of the parameters, however, relate to the called party. More importantly, Wulkan fails to adequately account for the disparate line quality provided by each different carrier.
More particularly, column 15, line 51 through column 16, line 14 of the Wulkan specification teaches a “performance monitor” with which the quality of a telephone connection can be measured. Based upon this measurement, the carrier associated with the connection can be bypassed in future calls where it is determined that the carrier cannot provide a good connection. Still, according to column 15, lines 60–63 state quite explicitly that voice quality of a telephone call is measured subjectively by a caller who can key in a code for a “BAD” call. Based only upon the caller's determination that a particular carrier provides poor voice quality, the carrier can be bypassed for a second, most optimal carrier.
Notably, certain call performance data can be collected without user intervention in the Wulkan system. Specifically, as recited in column 16, lines 1–4, automatically acquired performance data includes calls which have not been established due to lack of a ring tone or a busy tone, congestion tone, or short call duration. Thus, the Wulkan system can only provide for a low-tech analysis of voice quality, as a result, Wulkan cannot adequately compare in an objective, repeatable manner line quality from carrier to carrier. Rather, in Wulkan, a carrier is either acceptable or “bad”. Accordingly, one seeking to solve the problem of LCR in relation to optimizing the delivery of an electronic document through a selected carrier over the PSTN or an IP network would not turn to the deficient teachings of Wulkan.
Unlike Wulkan, U.S. Pat. No. 6,285,753 issued on Sep. 4, 2001 to Slusher for SYSTEM AND METHOD FOR LOCALLY INTELLIGENT AND ADAPTIVE DIALING OF TELEPHONE AND OTHER NETWORK ACCESS NUMBERS relates to the stochastic determination that a telephone number has been misdialed. Particularly, in the Slusher system, statistics are compiled that reflect the likelihood that a dialed network access code is invalid. Based upon the compiled statistics, the Slusher system can predict when a dialer has erred in providing the code. Thus, while Slusher stands for the proposition that predictive dialing can be applied to pre-empt a misdialed phone number, Slusher fails to address the crux of the problem—call routing for a specified target recipient of an electronic document across carriers having disparate levels of connection quality.
Notably, the teachings of U.S. Pat. No. 6,023,470 issued on Feb. 8, 2000 to Lee et al. for POINT OF PRESENCE (POP) FOR DIGITAL FACSIMILE NETWORK WITH VIRTUAL POPS USED TO COMMUNICATE WITH OTHER NETWORKS relates directly to IP faxing technology. As it will be recognized by the skilled artisan, some routing logic disclosed in Lee addresses the occasional failed attempt to deliver a fax to a recipient where the destination facsimile device cannot be accessed because the line is busy, out-of-service, or because a human voice answers the phone. In remediation of the failed attempt, the sender can be notified so that the sender can reattempt transmission at a later time rather than repeatedly dialing the number of the recipient.
Notwithstanding the foregoing references to the prior art, one skilled in the art will recognize several deficiencies inherent to conventional LCR technology. First, conventional LCR technology fails to account for varying levels of quality among different carriers when applying LCR logic to a specific attempt to transmit a document. Rather, LCR remains primarily focused upon cost savings. The same can be said of non-PSTN, IP devices such as routers, terminals, and the like which may have associated therewith vary degrees of transmission latency, traffic, and IP transport parameters. Second, conventional LCR technology fails to apply a probabilistic analysis to LCR logic based upon accumulated connection statistics. Accordingly, because LCR remains primarily focused upon cost efficiencies without considerable regard to effective communicative links, conventional LCR technology cannot provide optimal routing of an electronic document.